main.go

package main

import (
	"embed"
	"encoding/json"
	"errors"
	"flag"
	"io/fs"
	"log"
	"net/http"
	"os"
	"strings"

	"github.com/kradalby/kraweb"
)

const defaultHostname = "hugin"

var (
	verbose = flag.Bool("verbose", false, "be verbose")

	tailscaleKeyPath = flag.String(
		"tailscale-auth-key-path",
		"",
		"path to tailscale auth key, can be passed as TS_AUTH_KEY",
	)

	hostname = flag.String("hostname", defaultHostname, "service name")

	albumDir = flag.String("album", "", "directory containing a Munin album")

	controlURL = flag.String("controlurl", "", "Tailscale Control server, if empty, upstream")

	localAddr = flag.String("addr", "localhost:56664", "Local address to listen to")
)

func main() {
	if err := Run(); err != nil {
		log.Fatalf("failed to start hugin: %s", err)
	}
}

func tokenHandler() http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		tokens := make(map[string]string)
		env := os.Environ()

		for _, kv := range env {
			if rest, ok := strings.CutPrefix(kv, "HUGIN_TOKEN_"); ok {
				parts := strings.Split(rest, "=")

				tokens[strings.ToLower(parts[0])] = parts[1]
			}
		}

		json.NewEncoder(w).Encode(tokens)
	})
}

//go:embed dist/*
var distFS embed.FS

func distHandler() http.Handler {
	sub, err := fs.Sub(distFS, "dist")
	if err != nil {
		log.Fatal(err)
	}

	return http.FileServer(http.FS(sub))
}

func loggingHandler(h http.Handler, dir string) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		log.Printf("%s - %s: %s", r.Method, r.URL.Path, dir+r.URL.Path)
		h.ServeHTTP(w, r)
	})
}

func Run() error {
	flag.Parse()

	logger := log.New(os.Stdout, "hugin: ", log.LstdFlags)

	k := kraweb.NewKraWeb(
		*hostname,
		*tailscaleKeyPath,
		*controlURL,
		*verbose,
		*localAddr,
		logger,
		true,
	)

	k.Handle("/", distHandler())
	k.Handle("/tokens", tokenHandler())

	if *albumDir == "" {
		log.Printf("--album is required to serve an album")
	} else {
		log.Printf("Serving content from %s", *albumDir)
		k.Handle("/album/", http.StripPrefix("/album", loggingHandler(http.FileServer(http.Dir(*albumDir)), *albumDir)))
		k.Handle("/content/", http.StripPrefix("/content", loggingHandler(http.FileServer(http.Dir(*albumDir)), *albumDir)))
	}

	if *hostname == "" {
		return errors.New("--hostname, if specified, cannot be empty")
	}

	return k.ListenAndServe()
}